Augment element for prosthesis, in particular for knee prosthesis

ABSTRACT

An augment element for tibial applications in a knee prosthesis. The augment element comprises a metal body of a substantially truncated conical shape configured to be inserted into a bone extremity and having an outer surface comprising a metal trabecular surface The the metal body is hollow with an axial through-cavity defining a plurality of substantially annular transversal sections. The metal body is inclined in a direction of inclination, so as to define at least one eccentricity between a first transversal section at a first end of the axial through-cavity and a second transversal section at a second end of the axial through-cavity The first transversal section at the first end is larger in size than the second transversal section at the second end. The metal body comprises lateral walls having respective curved and concave shapes with respect to the outside of the metal body, to replicate a medial/side and rear bone anatomy.

DESCRIPTION Field of Application

The present invention refers to an augment element for prosthesiscomprising a metal body of a substantially truncated conical shapeconfigured to be inserted in a bone extremity.

The invention is particularly useful in the surgical interventions ofknee prosthesis implantation and the following description is made withreference to this specific field of application in order to simplify theexposition thereof.

In general, it is not excluded that the present invention could beapplied in other types of surgical interventions of prosthesisimplantation in bone extremities.

Prior Art

In the orthopaedic surgery for the implantation of a prosthesis, a boneseat is sometimes subjected to the application of an augment element,typically applied in a housing milled in the bone with a desiredprofile.

In the context of the present description, with the term “augmentelement” is meant a prosthesis element capable of filling or taking theplace of a bone portion cut or degraded due to pre-existing pathologiesor implantations and further capable of being connected to furtherprosthesis joint elements in order to provide a stable implantation.

The usage of an augment element is particularly common when a spongypart of the bone is not able to support by itself the prosthesis,especially in the case of knee or hip prosthesis.

Typically, an augment element is a substantially cone-shaped ortruncated cone-shaped component made of metal.

For example, a knee prosthesis typically comprises a femoral componentwhich is fixed to the distal extremity of a femur, and a tibialcomponent which is fixed to the proximal extremity of a tibia. In thatcase, both an augment element for the extremity of the femur, and anaugment element for the extremity of the tibia can be provided.

The document WO2015/145348 (A1) relates to a multilayered augmentelement for prosthesis, comprising a body of truncated conical shapewith an axial through-cavity open at both ends and an annular section.The body comprises an outer portion of metal trabecular material.

The document US2019/070008 (A1) relates to an augment element forprosthesis, comprising a hollow sleeve with an internal channel whichcrosses it. The hollow sleeve comprises one or more bending joints,configured for compressing the channel and reducing the circumferenceand width of the hollow sleeve. The body is of metal material, withouttrabecular portions.

A difficulty which emerges in the prior art is that the known augmentelements are not able to precisely correspond with the bone anatomy,thus making the performances of the implanted prosthesis unsatisfactory.

In particular, since both tibia and femur have an asymmetric elongatedconfiguration, known augment elements are not able to match the specifictibial or femoral bone anatomy of the patient.

Furthermore, in the prior art, there are problems regarding theinsertion or removal of augment elements in the respective bone seat,which involve surgical complexity or difficulty.

A general object of the present invention is to provide to the surgeonan augment element which solves some drawbacks of the prior art.

A further object of the present invention is to allow an augment elementto better adapt to the specific bone anatomy.

A further object of the present invention is to provide an augmentelement particularly suitable for a specific tibial or femoral boneanatomy of a patient.

A further object of the present invention is to give an augment elementwhich is more efficient during insertion or removal in the respectivebone seat.

SUMMARY OF THE INVENTION

The solution idea underlying the present invention is to provide anaugment element for prosthesis configured to be inserted in a boneextremity, having a metal body of a substantially truncated shape withan axial cavity. The metal body has a plurality of annular sectionsdefined along the axial cavity, which are eccentrically stacked so as todefine a global inclination of the metal body. The configuration of themetal body allows to better adapt to the specific bone anatomy, inparticular for femoral or tibial applications. Additionally, a metaltrabecular surface, preferably obtained in one piece and seamlessly withthe metal body, can be provided to further improve implantation andattachment on the bone seat.

Based on such solution idea, an augment element for prosthesis, inparticular for knee prosthesis, is provided which comprises a metal bodyof a substantially truncated conical shape and configured to be insertedin a bone extremity. The body has an outer surface preferably comprisinga metal trabecular surface. The metal body is hollow with an axialthrough-cavity defining a plurality of substantially annular transversalsections. Furthermore, the metal body is inclined in a direction ofinclination, so as to define at least one eccentricity between a firsttransversal section at a first end of the axial through-section and asecond transversal section at a second end of the axial through-cavity.

Thereby, an augment element particularly suitable for a specificasymmetric bone anatomy is provided, with particular advantage in caseof application of the augment element to a tibial or femoral boneextremity.

It is also provided that the augment element for prosthesis has a metalbody of a substantially truncated conical shape, with an axialthrough-cavity and comprising a metal trabecular surface. Preferably,the augment element further comprises a plurality of through-slits, openfrom a first end of the metal body up to an intermediate portion; suchslits are configured for a radial compression of the metal body, thuslocally reducing a circumference of the substantially annulartransversal section of the metal body.

Thereby, an augment element is advantageously provided which is moreefficient during the insertion and implantation, allowing a radialcompression of the metal body which increases the press-fit toward thebone; together with the increasing of the press-fit towards the bone,also the pressure of the trabecular surface against the bone increases,thus stimulating the bone growth in order to ensure a stable andlong-term connection.

The augment element according to the present invention advantageouslyimproves both the primary stability and the secondary stability of theimplantation. The primary stability is the one which is immediatelyobservable in the intervention, it is practically a mechanic wedging.The secondary stability is instead obtained due to the osseointegration,which is improved by the presence of primary stability, by the presenceof a trabecular structure or with adequate porosity and by the presenceof a compression force or press-fit which stimulates the bone growth.

Furthermore, specific features of the augment element are provided whichmake it particularly efficient in case of applications to tibial orfemoral extremities, which will be illustrated in detail in thefollowing.

Further features and advantages of the invention will become apparentfrom the detailed description which follows, provided for illustrativeand non-limiting purposes, and from the claims which form an integralpart of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a prospective view of a first embodiment of augment elementfor prosthesis according to the present invention.

FIG. 2 shows a frontal view of the first embodiment of augment elementfor prosthesis.

FIG. 3 shows a lateral sectional view of the first embodiment of augmentelement for prosthesis.

FIG. 4 shows a lateral view of the first embodiment of augment elementfor prosthesis.

FIG. 5 shows a frontal sectional view of the first embodiment of augmentelement for prosthesis.

FIG. 6 shows a bottom view of the first embodiment of augment elementfor prosthesis.

FIG. 7 shows a frontal view of the first embodiment of augment elementfor prosthesis with further geometrical indications.

FIG. 8 shows a lateral view of the first embodiment of augment elementfor prosthesis with further geometrical indications.

FIG. 9 shows a prospective view of a second embodiment of augmentelement for prosthesis according to the present invention.

FIG. 10 shows a frontal view of the second embodiment of augment elementfor prosthesis.

FIG. 11 shows a lateral sectional view of the augment element forprosthesis.

FIG. 12 shows a lateral view of the second embodiment of augment elementfor prosthesis.

FIG. 13 shows a frontal sectional view of the second embodiment ofaugment element for prosthesis.

FIG. 14 shows a frontal view of the second embodiment of augment elementfor prosthesis with further geometrical indications.

FIG. 15 shows a lateral view of the second embodiment of augment elementfor prosthesis with further geometrical indications.

FIG. 16 shows a prospective view of a third embodiment of augmentelement for prosthesis according to the present invention.

FIG. 17 shows a frontal view of the third embodiment of augment elementfor prosthesis.

FIG. 18 shows a lateral sectional view of the third embodiment ofaugment element for prosthesis.

FIG. 19 shows a lateral view of the third embodiment of augment elementfor prosthesis.

FIG. 20 shows a frontal sectional view of the third embodiment ofaugment element for prosthesis.

FIG. 21 shows a frontal view of the third embodiment of augment elementfor prosthesis with further geometrical indications.

FIG. 22 shows a lateral view of the third embodiment of augment elementfor prosthesis with further geometrical indications.

FIG. 23 shows a top view of the third embodiment of augment element forprosthesis.

FIG. 24 shows a prospective view of a fourth embodiment of augmentelement for prosthesis according to the present invention.

FIG. 25 shows a frontal view of the fourth embodiment of augment elementfor prosthesis.

FIG. 26 shows a lateral sectional view of the fourth embodiment ofaugment element for prosthesis.

FIG. 27 shows a lateral view of the fourth embodiment of augment elementfor prosthesis.

FIG. 28 shows a frontal sectional view of the fourth embodiment ofaugment element for prosthesis.

FIG. 29 shows a top view of the fourth embodiment of augment element forprosthesis.

FIG. 30 shows a frontal view of the fourth embodiment of augment elementfor prosthesis with further geometrical indications.

FIG. 31 shows a lateral view of the fourth embodiment of augment elementfor prosthesis with further geometrical indications.

FIG. 32 shows a prospective view of a variation of the fourth embodimentof augment element for prosthesis.

FIG. 33 shows a further prospective view of a variation of the fourthembodiment of augment element for prosthesis.

FIG. 34 shows an example of application of the second embodiment ofaugment element for prosthesis to a femoral extremity.

FIG. 35 shows an example of application of the third embodiment ofaugment element for prosthesis to a tibial extremity.

In different figures, analogous elements will be indicated by analogousreference numbers.

The technical drawings presented in the figures are to be understood aspurely illustrative, not necessarily made to scale or having the samescale among each other.

DETAILED DESCRIPTION

FIG. 1 shows a prospective view of a first embodiment of augment element100 for prosthesis according to the present invention. The augmentelement 100 of this example is an element for femoral application, incombination with a knee prosthesis.

The augment element 100 comprises a metal body 101 of a substantiallytruncated conical shape, which is configured to be inserted in a femoralextremity. Preferably, the metal body 101 is made of titanium or alloysthereof, for biomedical applications.

In general, the metal body comprises walls, which will be furtherdescribed, having a substantially constant thickness.

The metal body 101 has an outer surface comprising a metal trabecularsurface 102; preferably the metal trabecular surface 102 is obtained inone piece seamlessly with the metal body 101 by a co-manufactureprocedure, for example by EBM (Electron Beam Machining) technologies. Aco-manufacture procedure in fact allows to provide an interface-freemetal trabecular surface, so as to avoid the risk of detachments of thetrabecular part of the metal body.

The metal body 101 preferably comprises a smooth edge 103 on the outersurface surrounding the metal trabecular surface 102 on one or moresides, preferably on all sides.

The metal body 101 is hollow with an axial through-cavity 104 defining aplurality of substantially annular transversal sections, whoseconfiguration will be further described.

FIG. 2 shows a frontal view of the augment element 100 for prosthesis,wherein the two symmetric lateral walls of the same are shown, having asame inclination.

FIG. 3 shows a lateral sectional view of the augment element 100 forprosthesis, with respect to section III-III of FIG. 2 .

The metal body 101 is inclined in a direction of inclination, in thiscase towards the right of the figure, so as to define an eccentricitybetween a first transversal section at a first end 105 of the axialthrough-cavity 104 and a second transversal section at a second end 106of the axial through-cavity 104.

In particular, the axial cavity 104 has a longitudinal axis 107 inclinedin the direction of inclination with respect to the vertical axis of themetal body 101. The vertical axis, not shown in the figure for the sakeof simplicity, is perpendicular to one of the first or secondtransversal section, at the respective end 105 or 106.

The metal body 101 comprises a frontal wall 108 extended towards thedirection of inclination, and a rear wall 109 opposite the frontal wall108 and extended away from the direction of inclination.

The frontal wall 108 has an inclination with respect to the verticalaxis that is less than an inclination of the rear wall 109.

In other words, the profile of the metal body 101 is tapered towards thefirst end 105, with a frontal asymmetry visible in lateral section.

FIG. 4 shows a lateral view of the augment element 100 for prosthesis,wherein some features already discussed in relation to FIG. 3 arepointed out.

FIG. 5 shows a frontal sectional view of the augment element 100 forprosthesis, with respect to section V-V of FIG. 4 .

In this embodiment, it is appreciated how the longitudinal axis 107 ofthe cavity 104 is instead not inclined with respect to a vertical axisof the metal body 101, considering the direction transversal to thedirection of inclination shown in FIG. 3 .

The augment element 100 further comprises a plurality of through-slits110 in the metal body 101, which are open from the first end 105 up toan intermediate portion on the metal body 101.

These slits 110 are configured for a radial compression of the metalbody 101, in particular facilitating the insertion in a femoral cavity,locally reducing a circumference of the substantially annulartransversal sections which make up the metal body 101 during insertionof the augment element 100, and increasing a press-fit towards a boneportion.

In particular, for femoral applications, the first transversal sectionat the end 105 is smaller in size with respect to the second transversalsection at the end 106, so as to facilitate an insertion of the metalbody 101 into the femoral bone extremity.

Preferably, each of the slits 110 is open towards the first end 105 andends in a respective enlarged circular hole 111 beside to theintermediate portion of the metal body 101. Thereby, the enlargedcircular hole 111 is configured to improve a localized mechanicalresistance of the metal body.

FIG. 6 shows a bottom view of the augment element 100 for prosthesis. Inthis view it is possible to appreciate the eccentricity 112 resultingbetween the first transversal (in this case, circular) section at thefirst end 105, and the second transversal (in this case, circular)section at the second end 106 of the axial through-cavity 104.

FIG. 7 shows a frontal view of the augment element 100 for prosthesiswith geometrical indications relating to the metal body 101.

In particular, the conicity 113 of the symmetric lateral walls isoverall comprised between 6° and 10°, more preferably equal to 8.5°.

FIG. 8 shows a lateral view of the augment element 100 for prosthesiswith geometrical indications relating to the metal body 101.

In the example of the augment element 100, the frontal wall 108 isvertical that is with inclination of 0° with respect to the vertical. Ingeneral, an inclination of the frontal wall 108 with respect to thevertical axis can be comprised between 0° and 5°, more preferablycomprised between 0° and 2°.

In the example of the augment element 100, the rear wall 108 has aninclination 114 of 8.5° with respect to the vertical. In general, aninclination of the rear wall 108 with respect to the vertical axis iscomprised between 6° and 10°.

FIG. 9 shows a prospective view of a second embodiment of augmentelement 200 for prosthesis according to the present invention. Theaugment element 200 of this example is an element for femoralapplication, in combination with a knee prosthesis.

The augment element 200 comprises a metal body 201 of a substantiallytruncated conical form, which is configured to be inserted in a femoralextremity. Preferably, the metal body 201 is made of titanium or alloysthereof, for biomedical applications.

The metal body 201 has an outer surface comprising a metal trabecularsurface 202; preferably the metal trabecular surface 202 is directlyapplied to the metal body 201 by a co-manufacture procedure in one pieceand seamlessly, for example by EBM (Electron Beam Machining)technologies.

The metal body 201 preferably comprises a smooth edge 203 on the outersurface surrounding the metal trabecular surface 202 on one or moresides, preferably on all sides.

The metal body 201 is hollow with an axial through-cavity 204 defining aplurality of substantially annular transversal sections, whoseconfiguration will be further described.

FIG. 10 shows a frontal view of the augment element 200 for prosthesis,wherein it is evident a pair of bicondylar supports 220 a and 220 b,arranged sideways in the metal body 201.

The bicondylar supports 220 a and 220 b protrude from a terminaltransversal section of the body 201, and each comprises a tapered body,which widens away from the metal body 201.

Preferably, also the bicondylar supports 220 a and 220 b have an outersurface comprising a metal trabecular surface, made in one piece andseamlessly with the bicondylar supports 220 a and 220 b.

In the augment element 200, the bicondylar supports 220 a and 220 bperform a support function also for the femoral condyles, in case thatthe bone defect will be extended also to the latter. The choice betweenthe embodiment 100 without bicondylar supports or 200 comprising thebicondylar supports of the augment element, may depend for example onthe location and extension of the bone defect. For example, in case of aremoval of an implantation with stem, there is often the generation of afemoral bone defect along the channel, for which it would be preferredto use an augment element 100 according to the first embodiment;differently, in case of advanced bone degeneration, a situation mayarise where the femoral condyle will not offer sufficient support for aprosthesis, and it would be preferred to use an augment element 200according to the second embodiment, in order to obtain a greaterreinforcement of the area.

Preferably, the metal body comprises a smooth edge 203 on the outersurface, which surrounds at least partially the metal trabecular surface202 and preferably also the metal trabecular surface of the bicondylarsupports 220 a and 220 b.

FIG. 11 shows a lateral sectional view of the augment element 200 forprosthesis, with respect to section XI-XI of FIG. 10 .

The metal body 201 is inclined in a direction of inclination, in thiscase towards the right of figure, so as to define an eccentricitybetween a first transversal section at a first end 205 of the axialthrough-cavity 204 and a second transversal section at a second end 206of the axial through-cavity 204.

In particular, the axial cavity 204 has a longitudinal axis 207 inclinedin the direction of inclination with respect to a vertical axis of themetal body 201. The vertical axis, not shown in the figure for sake ofsimplicity, is perpendicular to one of the first or second transversalsection, at the respective end 205 or 206.

The metal body 201 comprises a frontal wall 208 extended towards thedirection of inclination, and a rear wall 209 opposite the frontal wall208 and extended away from the direction of inclination.

The frontal wall 208 has an inclination with respect to the verticalaxis that is less than an inclination of the rear wall 209.

In other words, the profile of the metal body 201 is tapered towards thefirst end 205, with a frontal asymmetry visible in lateral section.

In fact, an eccentricity between the first transversal section at thefirst end 205, and the second transversal section at the second end 206of the axial through-cavity 204 can be guessed.

FIG. 12 shows a lateral view of the augment element 200 for prosthesis,wherein some features already discussed in relation to FIG. 11 arepointed out.

FIG. 13 shows a frontal sectional view of the augment element 200 forprosthesis, with respect to section XIII-XIII of FIG. 12 .

The augment element 200 further comprises a plurality of through-slits210 in the metal body 201, which are open from the first end 205 up toan intermediate portion on the metal body 201.

These slits 210 are configured for a radial compression of the metalbody 201, in particular facilitating the insertion in a femoral cavity,locally reducing a circumference of the substantially annulartransversal sections which make up the metal body 201 during insertionof the augment element 200, and increasing a press-fit towards a boneportion.

In particular, for femoral applications, the first transversal sectionat the end 205 is smaller in size with respect to the second transversalsection at the end 206, so as to facilitate an insertion of the metalbody 201 into the femoral bone extremity.

Preferably, each of the slits 210 is open towards the first end 205 andends in a respective enlarged circular hole 211 beside to theintermediate portion of the metal body 201. Thereby, the enlargedcircular body 211 is configured to improve a localized mechanicalresistance of the metal body.

In the augment element 200 for femoral applications, the firsttransversal section at the end 205 is smaller in size with respect tothe second transversal section at the end 206, and the pair ofbicondylar supports 220 a e 220 b arranged sideways protrude preciselyfrom the second transversal section, thus being in distal position oncethe augment element is implanted in the respective femoral bone cavity.

FIG. 14 shows a frontal view of the augment element 200 for prosthesiswith geometrical indications relating to the metal body 201.

In particular, the conicity 213 of the lateral walls is overallcomprised between 6° and 10°, more preferably equal to 8.5° as in theexample of the augment element 200.

As visible, the second transversal section at the end 206 is furthermoreinclined in a second direction of inclination, in a plane transversal tothe direction of inclination of the longitudinal axis 207. In thatsense, the metal body 201 has a plane of inclination of the end 206which is different with respect to the plane of inclination of the end205, generating an overall asymmetry of the augment element 201, notonly in the already-considered direction of frontal inclination, butalso in a direction of transversal inclination of the whole metal body201, visible in FIG. 14 .

Furthermore, the pair of bicondylar supports 220 a and 220 b extendsfrom the second end 206 by a same height 221, thus defining anasymmetric pair of bicondylar supports 220 a and 220 b.

In the light of the overall asymmetry of the augment element 200, it isclear that different solutions for a left or right femur must beprovided.

FIG. 15 shows a lateral view of the augment element 200 for prosthesiswith geometrical indications relating to the metal body 201.

In the example of the augment element 200, the frontal wall 208 isvertical that is with inclination of 0° with respect to the vertical. Ingeneral, an inclination of the frontal wall 208 with respect to thevertical axis can be comprised between 0° and 5°, more preferablycomprised between 0° and 2°.

In the example of the augment element 200, the rear wall 209 has aninclination 214 of 8.5° with respect to the vertical. In general, aninclination of the rear wall 209 with respect to the vertical axis iscomprised between 6° and 10°.

FIG. 16 shows a prospective view of a third embodiment of augmentelement 300 for prosthesis according to the present invention. Theaugment element 300 of this example is an element for tibialapplication, in combination with a knee prosthesis.

The augment element 300 comprises a metal body 301 of a substantiallytruncated conical shape, which is configured to be inserted in a tibialextremity. Preferably, the metal body 301 is made of titanium or alloysthereof, for biomedical applications.

The metal body 301 has an outer surface comprising a metal trabecularsurface 302; preferably the metal trabecular surface 302 is directlyapplied to the metal body 301 by a co-manufacture procedure in one pieceand seamlessly, for example by EBM (Electron Beam Machining)technologies.

The metal body 301 preferably comprises a smooth edge 303 on the outersurface surrounding the metal trabecular surface 302 on one or moresides, preferably on all sides.

The metal body 301 is hollow with an axial through-cavity 304 defining aplurality of substantially annular transversal sections, whoseconfiguration will be further described.

In a natural analogy, the metal body 301 is similar to a flower corollashape from which two opposed petals were removed.

FIG. 17 shows a frontal view of the augment element 300 for prosthesis,wherein the two symmetric lateral walls of the same are shown, having asame inclination and configuration.

FIG. 18 shows a lateral sectional view of the augment element 300 forprosthesis, with respect to section XVIII-XVIII of FIG. 17 .

The metal body 301 is inclined in a direction of inclination, in thiscase towards the right of the figure, so as to define an eccentricitybetween a first transversal section at a first end 305 of the axialthrough-cavity 304 and a second transversal section at a second end 306of the axial through-cavity 304.

In particular, the axial cavity 304 has a longitudinal axis 307 inclinedin the direction of inclination with respect to a vertical axis of themetal body 301. The vertical axis, not shown in the figure for the sakeof simplicity, is perpendicular to one of the first or secondtransversal section, at the respective end 305 or 306.

The metal body 301 comprises a frontal wall 308 extended towards thedirection of inclination, and a rear wall 309 opposite the frontal wall308 and extended away from the direction of inclination.

The frontal wall 308 has an inclination with respect to the verticalaxis that is less than an inclination of the rear wall 309.

In other words, the profile of the metal body 301 is tapered towards thesecond end 306, with a frontal asymmetry visible in lateral section.

FIG. 19 shows a lateral view of the augment element 300 for prosthesis,wherein some features already discussed in relation to FIG. 18 arepointed out.

For tibial applications, it can be seen that the first transversalsection at the end 305 is larger in size with respect to the secondtransversal section at the end 306, so as to facilitate an insertion ofsaid metal body into the tibial bone extremity.

The augment element 300 further comprises a pair of cut-outs 320arranged sideways in the metal body 301, and open from the first end 305up to an intermediate portion on the metal body 301.

FIG. 20 shows a frontal sectional view of the augment element 300 forprosthesis, with respect to section XX-XX of FIG. 19 .

In this embodiment, it is appreciated how the longitudinal axis 307 ofthe cavity 304 is instead not inclined with respect to a vertical axisof the metal body 301, considering the direction transversal to thedirection of inclination shown in FIG. 18 .

FIG. 21 shows a frontal view of the augment element 300 for prosthesiswith geometrical indications relating to the metal body 301.

Preferably, the metal body 301 comprises lateral walls 321 at thecut-outs 320; such lateral walls 321 have respective curved and concaveshapes with respect to the outside of the metal body 301, to replicate amedial/side and rear bone anatomy.

In particular, an overall conicity 313 of the symmetric lateral walls321, measured with respect to imaginary straight lines passing throughthe two edges of the metal body 301, respectively at the first end 305and the second end 306, is overall comprised between 12° and 20°, morepreferably equal to 18°.

FIG. 22 shows a lateral view of the augment element 300 for prosthesiswith geometrical indications relating to the metal body 301.

In the example of the augment element 300, the frontal wall 308 is nearthe vertical, with an inclination 315 equal to 2° with respect to thevertical. In general, an inclination of the frontal wall 308 withrespect to the vertical axis can be comprised between 0° and 5°, morepreferably comprised between 0° and 2°.

In the example of the augment element 300, the rear wall 309 has aninclination of 16° with respect to the vertical. In general, aninclination of the rear wall 309 with respect to the vertical axis iscomprised between 15° and 20°.

Preferably, the rear wall 309 further has a curved and concave shapewith respect to the outside of the metal body 301, to replicate a tibialbone rear anatomy.

FIG. 23 shows a top view of the augment element 300 for prosthesis.

In this view, it is possible to appreciate the eccentricity 312resulting between the first transversal section (in this case, circular)at the first end 305 and the second transversal section (in this case,circular) at the second end 306 of the axial through-cavity 304.

FIG. 24 shows a prospective view of a fourth embodiment of augmentelement 400 for prosthesis according to the present invention. Theaugment element 400 of this example is an element for tibialapplication, in combination with a knee prosthesis.

The augment element 400 comprises a metal body 401 of a substantiallytruncated conical shape, which is configured to be inserted in a tibialextremity. Preferably, the metal body 401 is made of titanium or alloysthereof, for biomedical applications.

The metal body 401 has an outer surface comprising a metal trabecularsurface 402; preferably the metal trabecular surface 402 is directlyapplied to the metal body 401 by a co-manufacture procedure, made in onepiece and seamlessly, for example by EBM (Electron Beam Machining)technologies.

The metal body 401 preferably comprises a smooth edge 403 on the outersurface surrounding the metal trabecular surface 402 on one or moresides, preferably on all sides.

The metal body 401 is hollow with an axial through-cavity 404 defining aplurality of substantially annular transversal sections, whoseconfiguration will be further described.

FIG. 25 shows a frontal view of the augment element 400 for prosthesis,wherein the two symmetric lateral walls 421 of the same are shown,having a same inclination and configuration.

FIG. 26 shows a lateral sectional view of the augment element 400 forprosthesis, with respect to section XVI-XVI of FIG. 25 .

The metal body 401 is inclined in a direction of inclination, in thiscase towards the right of the figure, so as to define at least oneeccentricity between a first transversal section at a first end 405 ofthe axial through-cavity 404 and a second transversal section at asecond end 406 of the axial through-cavity 404.

In particular, the axial cavity 404 has a longitudinal axis 407 inclinedin the direction of inclination with respect to a vertical axis of themetal body 401. The vertical axis, not shown in the figure for the sakeof simplicity, is perpendicular to one of the first or secondtransversal section, at the respective end 405 or 406.

The metal body 401 comprises a frontal wall 408 extended towards thedirection of inclination and a rear wall 409 opposite the frontal wall408 and extended away from the direction of inclination.

The frontal wall 408 has an inclination with respect to the verticalaxis that is less than an inclination of the rear wall 409.

In other words, the profile of the metal body 401 is tapered towards thesecond end 406, with a frontal asymmetry visible in lateral section.

FIG. 27 shows a lateral view of the augment element 400 for prosthesis,wherein some features already discussed in relation to FIG. 26 arepointed out.

For tibial applications, it can be seen that the first transversalsection at the end 405 is larger in size with respect to the secondtransversal section at the end 406, so as to facilitate an insertion ofsaid metal body into the tibial bone extremity.

The augment element 400 further comprises a pair of cut-outs 420arranged sideways in the metal body 401, and open from the first end 405up to an intermediate portion on the metal body 401.

FIG. 28 shows a frontal sectional view of the augment element 400 forprosthesis, with respect to section XXVIII-XXVIII of FIG. 27 .

In this embodiment, it is appreciated how the longitudinal axis 407 ofthe cavity 404 is instead not inclined with respect to a vertical axisof the metal body 401, considering the direction transversal to thedirection of inclination shown in FIG. 26 .

FIG. 29 shows a top view of the augment element 400 for prosthesis,wherein it is appreciated that the first transversal section at the end405 is bilobed annular, such that the outer surface of the metal body401 is tapered between the first transversal section and the secondtransversal section, as better visible in FIG. 24 .

In a natural analogy, the metal body 401 is similar to a flower corollashape from which two opposed petals were removed.

In this view, it is also possible to appreciate the double eccentricity412 resulting between the first transversal section (in this case,bilobed therefore having two circumference centres which describe it) atthe first end 405, and the second transversal section (in this case,circular with only one circumference centre) at the second end 406 ofthe axial through-cavity 404.

FIG. 30 shows a frontal view of the augment element 400 for prosthesisfor prosthesis with geometrical indications relating to the metal body401.

Preferably, the metal body 401 comprises lateral walls 421 at thecut-outs 420; such lateral walls 421 have respective curved and concaveshapes with respect to the outside of the metal body 401, to replicate amedial/side and rear bone anatomy.

In particular, an overall concavity 413 of the lateral symmetric walls421 is overall comprised between 45° and 55°, more preferably equal to50°.

FIG. 31 shows a lateral view of the augment element 400 for prosthesiswith geometrical indications relating to the metal body 401.

In the example of the augment element 400, the frontal wall 408 is nearthe vertical, with an inclination 415 equal to 2° with respect to thevertical. In general, an inclination of the frontal wall 408 withrespect to the vertical axis can be comprised between 0° and 5°, morepreferably comprised between 0° and 2°.

In the example of the augment element 400, the rear wall 409 has aninclination of 19.4° with respect to the vertical. In general, aninclination of the rear wall 409 with respect to the vertical axis iscomprised between 15° and 20°.

Preferably, the rear wall 409 further has a curved and concave shapewith respect to the outside of the metal body 401, to replicate a tibialbone rear anatomy.

FIGS. 32 and 33 show respective prospective views of a variation of theaugment element 400′ for prosthesis.

In this variation, the augment element 400′ comprises a plurality ofthrough-slits 410 in the metal body, open from the first end up to aintermediate portion on the metal body, which are configured for aradial compression of the metal body, locally reducing a circumferenceduring insertion of the augment element 400′, and increasing a press-fittowards a bone portion. Preferably, each of the slits 410 ends in arespective enlarged circular hole 411.

FIG. 34 shows an example of application of the augment element 200 forprosthesis to a femoral extremity.

FIG. 35 shows an example of application of the augment element 300 forprosthesis to a tibial extremity.

It is clear that further implementations and modifications of thepresent invention will be possible for the person skilled in the art, inorder to meet contingent needs.

In particular, specific features described with reference to anembodiment could be also applied to other embodiments described hereinin a variation thereof, if there is no technical prejudice in thisregard.

The above-described embodiments are therefore to be understood asprovided for illustrative and non-limiting purpose.

1. An augment element for tibial applications in a knee prosthesis, saidaugment element comprising a metal body of a substantially truncatedconical shape configured to be inserted into a bone extremity and havingan outer surface comprising a metal trabecular surface, said metal bodybeing hollow with an axial through-cavity defining a plurality ofsubstantially annular transversal sections, wherein said metal body isinclined in a direction of inclination, so as to define at least oneeccentricity between a first transversal section at a first end of saidaxial through-cavity and a second transversal section at a second end ofsaid axial through-cavity, wherein said first transversal section atsaid first end is larger in size than said second transversal section atsaid second end, and wherein said metal body comprises lateral wallshaving respective curved and concave shapes with respect to the outsideof said metal body, to replicate a medial/side and rear bone anatomy. 2.The augment element according to claim 1, wherein said axial cavity hasa longitudinal axis inclined in said direction of inclination withrespect to a vertical axis of said metal body, said vertical axis beingperpendicular to one of said first or second transversal section.
 3. Theaugment element according to claim 2, wherein said metal body comprisesa frontal wall extended towards said direction of inclination andfurther comprises a rear wall opposite said frontal wall and extendedaway from said direction of inclination, wherein said frontal wall hasan inclination with respect to said vertical axis that is less than aninclination of said rear wall.
 4. The augment element according to claim3, wherein an inclination of said frontal wall with respect to saidvertical axis is comprised between 0° and 5°.
 5. (canceled)
 6. Theaugment element according to claim 4, wherein for tibial applications aninclination of said rear wall with respect to said vertical axis iscomprised between 15° and 20°.
 7. The augment element according to claim6, wherein said rear wall further has a curved and concave shape withrespect to the outside of said metal body, to replicate a tibial bonerear anatomy.
 8. The augment element according to claim 1, furthercomprising a plurality of through-slits in said metal body, open fromsaid first end up to an intermediate portion on said metal body, whereinsaid plurality of through-slits is configured for a radial compressionof said metal body, locally reducing a circumference of saidsubstantially annular transversal sections during insertion of saidaugment element, and increasing a press-fit towards a bone portion. 9.(canceled)
 10. The augment element according to claim 8, wherein fortibial applications said first transversal section is larger in sizewith respect to said second transversal section, so as to facilitate aninsertion of said metal body into said tibial bone extremity.
 11. Theaugment element according to claim 8, wherein each of said plurality ofthrough-slits ends in a respective enlarged circular hole beside to saidintermediate portion, said enlarged circular hole being configured toimprove a localized mechanical resistance of said metal body . 12-15.(canceled)
 16. The augment element according to claim 1, furthercomprising a pair of cutouts arranged at said lateral walls and openfrom said first end up to an intermediate portion on said metal body.17. The augment element according to claim 1, wherein said firsttransversal section is bilobed annular and said second transversalsection is circular annular, said outer surface of said metal body beingtapered between said first transversal section and said secondtransversal section.
 18. The augment element according to claim 1,wherein said metal body comprises a smooth edge on said outer surfacesurrounding said metal trabecular surface.
 19. The augment elementaccording to claim 1, wherein said metal trabecular surface is made inone piece and seamlessly with said metal body.
 20. The ]augment elementaccording to claim 1, wherein said metal body comprises walls having asubstantially constant thickness.